Mahanine, a carbazole alkaloid (occurs in the edible part of Micromelum minutum, Murraya koenigii and related species), is a DNA minor groove binding agent with potent anticancer activity. Mahanine down regulates cell survival factors by activation of caspase-3 through mitochondrial dependent pathway. Mahanine was found to inhibit growth of PC3 and LNCaP prostate cancer cells in a dose and time-dependent manner. Mechanistically, mahanine inhibited cell-survival pathway by dephosphorylation of PIP3 dependent kinase 1 (PDK1) thereby deactivation of Akt and downregulation of Bcl-xL. In addition, mahanine activated caspase pathway (caspases 9 and 3) and eventually cleavage of DNA repair enzyme, PARP resulting DNA fragmentation and apoptosis.